JP2015002015A - Discharge lamp lighting device and luminaire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of ensuring the stability at starting up a discharge lamp without increasing the capacitance of a power supply capacitor of a switching element at the high side, and a luminaire using the same.SOLUTION: The discharge lamp lighting device includes: a first drive power supply (control power circuit 14) that outputs control voltage E1; a second drive power supply (auxiliary winding L3) that outputs a voltage which is proportional to a voltage output from a DC power circuit 10; a power supply capacitor C11 that supplies an operating voltage to a drive circuit of a switching element at the high side which maintains the ON state when at least starting a discharge lamp 3; and changeover means (first changeover circuit 15) that switches between a first path for charging a power supply capacitor C11 using the first drive power supply and a second path for charging the power supply capacitor C11 using the second drive power supply. The changeover means switches to the second path when starting a discharge lamp 3.

Description

  The present invention relates to a discharge lamp lighting device and a lighting device using the same.

  Conventionally, there has been known a discharge lamp lighting device that converts the output of a DC power source into a DC voltage required by a discharge lamp as a load, and converts this DC voltage into an alternating voltage and supplies it to the discharge lamp. It is disclosed in Patent Document 1.

  The high pressure discharge lamp lighting device described in Patent Document 1 includes a full bridge circuit that converts a DC voltage into an alternating voltage and applies the alternating voltage to the high pressure discharge lamp, and a control unit that controls the full bridge circuit. The full bridge circuit includes a first arm and a second arm each composed of a pair of two transistors. The full bridge circuit includes a bootstrap type first half bridge driver that drives the first arm and a bootstrap type second half bridge driver that drives the second arm. Further, the full bridge circuit includes a first bootstrap capacitor and a second bootstrap capacitor connected to each half bridge driver.

  Here, as a starting method for making a transition to a smooth arc discharge when starting the discharge lamp, a DC starting method in which a DC voltage is continuously applied to the discharge lamp is known. However, in this method, the high-side transistor of each arm can be turned on only by the discharge time of each bootstrap capacitor. For this reason, in the discharge lamp lighting device using the direct current starting method, a dedicated power source for continuing to supply a voltage to each bootstrap capacitor is required, and the cost increases.

  Therefore, in the high-pressure discharge lamp lighting device described in Patent Document 1, the high-pressure discharge lamp repeats the first period and the second period shorter than the first period in a predetermined period including immediately after the start of discharge. AC voltage is applied to In the first period, the bootstrap capacitor on one arm side is discharged while the high-side transistor of one arm and the low-side transistor of the other arm are turned on. In the second period, the bootstrap capacitor on one arm side is charged while the low-side transistor of one arm and the high-side transistor of the other arm are turned on.

  Therefore, in this high pressure discharge lamp lighting device, although the AC voltage is applied to the high pressure discharge lamp, the time for which the polarity is reversed is short, so that the startability equivalent to the DC start method is obtained. Further, in this high pressure discharge lamp lighting device, it is not necessary to provide a dedicated power source for continuing to supply a voltage to each bootstrap capacitor.

JP 2010-135195 A

  However, in the above conventional example, there is a period for charging the bootstrap capacitor (the power supply capacitor for the high-side switching element) when starting the discharge lamp, but the period is short. Therefore, in order to keep the transistors on the high side of each arm on to ensure the stability at the start of the discharge lamp, it is necessary to prepare a bootstrap capacitor with a large capacitance in consideration of the discharge time. is there. In this case, as the bootstrap capacitor becomes larger, there is a problem that the cost increases and the device becomes larger.

  In the conventional example, the polarity of the voltage applied to the high pressure discharge lamp is reversed during the charging period of the bootstrap capacitor. For this reason, there is a problem that there is a slight risk of the high pressure discharge lamp going off due to polarity reversal immediately after the start of discharge.

  The present invention has been made in view of the above points, and is a discharge lamp that can ensure the stability at the start of the discharge lamp without increasing the capacitance of the power supply capacitor of the high-side switching element. An object is to provide a lighting device and a lighting device using the lighting device.

  A discharge lamp lighting device according to the present invention includes a DC power supply circuit that outputs a DC voltage, an inverter circuit that converts an output voltage of the DC power supply circuit into an alternating voltage and outputs the alternating voltage, and an output voltage of the inverter circuit. Generating a high voltage pulse and starting the discharge lamp, and a control circuit for controlling each output of the DC power supply circuit and the inverter circuit, the inverter circuit at the time of starting the discharge lamp The inverter circuit continuously outputs a DC voltage of one polarity, and the inverter circuit includes a bridge circuit composed of at least two or more switching elements, a plurality of driving circuits that respectively drive the switching elements, and the switching elements. A power supply capacitor for supplying an operating voltage to the drive circuit for driving the switching element on the high side, A first drive power supply that outputs a voltage; and a second drive power supply that outputs a voltage that is proportional to the output voltage of the DC power supply circuit and that is higher than the voltage output by the first drive power supply at least when the discharge lamp is started. Switching means for switching between a first path for charging the power supply capacitor with the first drive power supply and a second path for charging the power supply capacitor with the second drive power supply, When the discharge lamp is started, it is switched to the second path.

  In this discharge lamp lighting device, it is preferable that the second drive power source is an auxiliary winding that is separately provided in a transformer or an inductor included in the DC power supply circuit and is electrically insulated from the DC power supply circuit.

  In this discharge lamp lighting device, it is preferable that the second drive power source is a charge pump type booster circuit that is connected to the DC power source circuit and boosts and outputs the output voltage of the DC power source circuit.

  In the discharge lamp lighting device, the second path is a path for supplying a current from the second drive power supply to the power supply capacitor via a current limiting resistor, and the switching unit is configured to output the second drive power supply. When the voltage to be output becomes higher than the voltage output from the first drive power supply, the second path is switched. When the voltage output from the first drive power supply becomes higher than the voltage output from the second drive power supply, the first path is set. It is preferable to be configured to switch to

  The illumination device of the present invention includes any one of the above-described discharge lamp lighting devices, a socket to which the discharge lamp is mounted, and a fixture main body that holds the discharge lamp lighting device and the socket.

  According to the present invention, when the discharge lamp is started, the power supply capacitor can be charged by the second drive power supply by switching to the second path. For this reason, in this invention, it is not necessary to ensure the charge time of the capacitor | condenser for power supplies, and it can employ | adopt the DC starting system which continues applying the DC voltage of one polarity to a discharge lamp. Therefore, in the present invention, it is possible to avoid the risk of the discharge lamp extinguishing due to polarity reversal immediately after the start of discharge. In the present invention, since the power supply capacitor can be continuously charged by the second drive power supply, it is not necessary to consider the discharge time of the power supply capacitor, and it is necessary to prepare a power supply capacitor having a large capacitance. Absent. That is, the present invention can ensure the stability at the start of the discharge lamp without increasing the capacitance of the power supply capacitor of the high-side switching element.

It is a circuit diagram which shows the discharge lamp lighting device which concerns on Embodiment 1 of this invention. It is an operation | movement waveform diagram of a discharge lamp lighting device same as the above. It is a circuit diagram which shows the discharge lamp lighting device which concerns on Embodiment 2 of this invention. It is an operation | movement waveform diagram of a discharge lamp lighting device same as the above. It is a circuit diagram which shows the discharge lamp lighting device which concerns on Embodiment 3 of this invention. It is a circuit diagram which shows the other structure of a discharge lamp lighting device same as the above. It is a circuit diagram which shows other structure of the discharge lamp lighting device same as the above. It is an operation | movement waveform diagram of another structure same as the above. It is a circuit diagram which shows the discharge lamp lighting device which concerns on Embodiment 4 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the vehicle headlamp which concerns on embodiment of this invention, (a) is schematic, (b) is a perspective view of a vehicle.

(Embodiment 1)
The discharge lamp lighting device 1 according to Embodiment 1 of the present invention includes a DC power supply circuit 10, an inverter circuit 11, a starting circuit 13, and a control circuit 12. The DC power supply circuit 10 outputs a DC voltage. The inverter circuit 11 converts the output voltage of the DC power supply circuit 10 into an alternating voltage and outputs it to the discharge lamp 3. The starting circuit 13 receives the output voltage of the inverter circuit 11 and generates a high voltage pulse to start the discharge lamp 3. The control circuit 12 controls the outputs of the DC power supply circuit 10 and the inverter circuit 11.

  The inverter circuit 11 continuously outputs a DC voltage of one polarity when the discharge lamp 3 is started. The inverter circuit 11 includes a bridge circuit composed of at least two (four in the present embodiment) switching elements Q11 to Q14, and a plurality of (four in the present embodiment) driving each of the switching elements Q11 to Q14. Circuits 110-140. The inverter circuit 11 includes a first driving circuit 110 that drives the high-side switching elements Q11 and Q13 among the switching elements Q11 to Q14, and power supply capacitors C11 and C13 that supply an operating voltage to the third driving circuit 130. .

  The discharge lamp lighting device 1 of the present embodiment includes a first drive power source that outputs a predetermined voltage, and a voltage that is proportional to the output voltage of the DC power supply circuit 10 and that is output from the first drive power source at least when the discharge lamp is started. And a second drive power source that outputs a higher voltage. The first drive power supply is a control power supply circuit 14. The second drive power source is the auxiliary winding L3. Further, the discharge lamp lighting device 1 according to the present embodiment switches switching means for switching between a first path for charging the power supply capacitor C11 by the first drive power supply and a second path for charging the power supply capacitor C11 by the second drive power supply. Have The switching means is the first switching circuit 15. In the discharge lamp lighting device 1 of the present embodiment, the first switching circuit 15 switches to the second path when the discharge lamp 3 is started.

  Hereinafter, a discharge lamp lighting device 1 according to Embodiment 1 of the present invention will be described with reference to the drawings. As shown in FIG. 1, the discharge lamp lighting device 1 of the present embodiment includes a DC power supply circuit 10, an inverter circuit 11, a control circuit 12, a starting circuit 13, a control power supply circuit 14, and a first switching circuit 15. With.

  The DC power supply circuit 10 boosts the input voltage V0 from the battery 2 which is a DC power supply, converts the voltage into a DC voltage necessary for lighting the discharge lamp 3, and outputs it. The DC power supply circuit 10 includes a step-up chopper circuit including a transformer 100 including a primary winding L1 and a secondary winding L2, a switching element Q1, a diode D1, and a smoothing capacitor C1. The switching element Q1 is switched on / off by a drive signal supplied from the control circuit 12 described later. The output voltage V1 of the DC power supply circuit 10 is adjusted by changing the switching cycle and the duty ratio of the switching element Q1.

  In the discharge lamp lighting device 1 of the present embodiment, a step-up chopper circuit is adopted as the DC power supply circuit 10, but a step-up / step-down chopper circuit, a flyback converter, or the like may be used. That is, the DC power supply circuit 10 may be configured to perform an operation of storing energy in the transformer 100 (inductor) when the switching element Q1 is turned on and discharging the stored energy when the switching element Q1 is turned off. In particular, the flyback converter can boost the voltage beyond the turns ratio of the transformer 100 and can obtain a wide range of output voltage, and thus is suitable for the DC power supply circuit 10 of the discharge lamp lighting device 1.

  Here, the voltage across the switching element Q1 is 0 V when the switching element Q1 is on. On the other hand, when the switching element Q1 is turned off, a boosted kickback voltage higher than the input voltage V0 is generated at both ends of the switching element Q1. This kickback voltage is rectified and smoothed by the diode D2 and the capacitor C2, and used as the power supply voltage E0. The power supply voltage E0 is expressed by E0 = (V1-V0) · N1 / N2 + V0 in the case of the step-up chopper circuit system as shown in FIG. In the above equation, N1 is the number of turns of the primary winding L1 of the transformer 100, N2 is the total number of turns of the primary winding L1 and the secondary winding L2 (via the diode D1 when the switching element Q1 is switched from on to off) The total number of windings in which current flows on the output side).

  Inverter circuit 11 includes a full bridge circuit composed of four switching elements Q11 to Q14, and four drive circuits 110 to 140 that drive each switching element Q11 to Q14. Each of switching elements Q11 to Q14 is configured by an n-channel MOSFET. In FIG. 1, the two switching elements Q11 and Q13 positioned on the upper side are referred to as “high-side” switching elements, and the two switching elements Q12 and Q14 positioned on the lower side are referred to as “low-side” switching elements.

  The first drive circuit 110 controls on / off of the switching element Q11 by controlling the gate voltage of the high-side switching element Q1. The first drive circuit 110 operates by being supplied with a charging voltage EQ1 of a power supply capacitor C11 which is a so-called bootstrap capacitor. The power supply capacitor C11 is charged by being supplied with the control voltage E1 via the diode D11. The control voltage E1 is an output voltage of the control power circuit 14 described later.

  The second drive circuit 120 controls on / off of the switching element Q12 by controlling the gate voltage of the low-side switching element Q12. The second drive circuit 120 operates by being supplied with the control voltage E1.

  The third drive circuit 130 controls on / off of the switching element Q13 by controlling the gate voltage of the high-side switching element Q13. The third drive circuit 130 operates by being supplied with the charging voltage EQ3 of the power supply capacitor C13 which is a so-called bootstrap capacitor. The power supply capacitor C13 is charged by being supplied with the control voltage E1 through the diode D13.

  The fourth drive circuit 140 controls on / off of the switching element Q14 by controlling the gate voltage of the low-side switching element Q14. The fourth drive circuit 140 operates by being supplied with the control voltage E1.

  The control circuit 12 is configured by a microcomputer, for example. The control circuit 12 controls the switching period and duty ratio of the switching element Q1 of the DC power supply circuit 10 based on the detection result of the output voltage and output current of the DC power supply circuit 10. With this control, the control circuit 12 controls the output voltage V1 of the DC power supply circuit 10 to a desired DC voltage. Since means for detecting the output voltage and output current of the DC power supply circuit 10 are well known in the art, description thereof is omitted here.

  In addition, the control circuit 12 controls the on / off of the switching elements Q11 to Q14 by giving drive signals to the drive circuits 110 to 140 of the inverter circuit 11. Specifically, the control circuit 12 outputs the voltage of one polarity from the inverter circuit 11 by switching the switching elements Q11 and Q14 on and switching the switching elements Q12 and Q13 off. The control circuit 12 outputs the voltage of the other polarity from the inverter circuit 11 by switching the switching elements Q11 and Q14 off and switching the switching elements Q12 and Q13 on. The control circuit 12 controls the alternating voltage output from the inverter circuit 11 by these controls.

  Here, when the switching elements Q11 and Q14 are on, the first drive circuit 110 uses the power supply capacitor C11 as a power supply. At this time, the control voltage E1 is supplied to the power supply capacitor C13 via the diode D13 and the switching element Q14. Therefore, the power supply capacitor C13 is charged while the inverter circuit 11 outputs a voltage of one polarity. When the switching elements Q12 and Q13 are on, the third drive circuit 130 uses the power supply capacitor C13 as a power supply. At this time, the control voltage E1 is supplied to the power supply capacitor C11 via the diode D11 and the switching element Q12. Therefore, the power supply capacitor C11 is charged while the inverter circuit 11 outputs the voltage of the other polarity.

  The starting circuit 13 includes a pulse driving circuit (not shown) and a pulse transformer (not shown). The start circuit 13 receives the output voltage of the inverter circuit 11 and generates a high voltage pulse for starting the discharge lamp 3 at the start of discharge of the discharge lamp 3 (that is, at the start). Then, the starter circuit 13 applies the generated high voltage pulse between the electrodes of the discharge lamp 3 in the extinguished state. Thereby, the starting circuit 13 starts the discharge lamp 3. Since the starting circuit 13 is conventionally known, the configuration and description thereof are omitted here.

  The control power supply circuit 14 includes a series regulator, and outputs a control voltage E1 that is a power supply voltage of the control circuit 12. The control power supply circuit 14 receives the power supply voltage E0 and outputs a constant voltage (for example, 10V). The control power supply circuit 14 is a “first drive power supply” that outputs a predetermined voltage (control voltage E1).

  When the switching operation of the switching element Q1 of the DC power supply circuit 10 starts, the charging voltage of the capacitor C2 rises above the input voltage V0. For this reason, even when the input voltage V0 of the battery 2 is lower than the control voltage E1, it is possible to stably obtain a voltage necessary for the operation of the control circuit 12.

  The transformer 100 of the DC power supply circuit 10 is separately provided with an auxiliary winding L3 having a winding number N3. The auxiliary winding L3 is electrically insulated from the DC power supply circuit 10. Both ends of the auxiliary winding L3 are connected in parallel to the power supply capacitor C11 via the first switching circuit 15 and the current limiting resistor R1. A zener diode ZD1 is connected in parallel to both ends of the power supply capacitor C11. The Zener diode ZD1 is selected such that the Zener voltage VZ1 is lower than the withstand voltage of each drive circuit 110-140.

  The first switching circuit 15 includes a comparator COM1 and a switch SW1. The auxiliary voltage V3 generated in the auxiliary winding L3 is input to the non-inverting input terminal of the comparator COM1. The reference voltage VB1 is input to the inverting input terminal of the comparator COM1. The switch SW1 is configured to be switched on / off by the output of the comparator COM1. That is, when the auxiliary voltage V3 is lower than the reference voltage VB1, the output of the comparator COM1 is at a low level, and the switch SW1 is turned off. On the other hand, when the auxiliary voltage V3 is higher than the reference voltage VB1, the output of the comparator COM1 becomes high level, and the switch SW1 is turned on.

  Hereinafter, the operation of the discharge lamp lighting device 1 of the present embodiment will be described with reference to FIG. When the operation of the apparatus is started, the control circuit 12 switches on the low-side switching elements Q12 and Q14. As a result, the control voltage E1 is supplied to the power supply capacitors C11 and C13 via the diodes D11 and D13, and the charging voltages EQ1 and EQ3 of the power supply capacitors C11 and C13 rapidly rise to the control voltage E1.

  Thereafter, the control circuit 12 controls the switching element Q1 to start controlling the DC power supply circuit 10. Immediately after the start of the apparatus, the discharge lamp 3 is turned off. Therefore, in order to start the discharge lamp 3, the control circuit 12 first sets the output voltage V1 of the DC power supply circuit 10 to a voltage (starting voltage) V10 (for example, 400 V) higher than the voltage (lighting voltage) V11 at the time of lighting. Raise. At this time, the auxiliary voltage V3 generated in the auxiliary winding L3 also increases. For example, when the input voltage V0 = 12.8V, the starting voltage V10 = 400V, and the turns ratio N1: N2 = 1: 6 of the transformer 100, the power supply voltage E0 rises to about 77.3V. That is, the auxiliary winding L3 functions as a “second drive power supply” that outputs a voltage proportional to the output voltage of the DC power supply circuit 10.

  Here, the auxiliary voltage V3 is represented by V3 = (V1-V0) · (N3 / N2). For example, if the input voltage V0 = 12.8V, the starting voltage V10 = 400V, and the turns ratio N1: N2: N3 = 2: 12: 1 of the transformer 100, the auxiliary voltage V3 rises to about 32.3V. Here, it is assumed that the control voltage E1 = 10V and the reference voltage VB1 = 15V. In this case, when the output voltage V1 of the DC power supply circuit 10 exceeds 192.8V, the switch SW1 is turned on. Then, a current is supplied from the auxiliary winding L3 to the power supply capacitor C11 via the current limiting resistor R1, and the charging voltage EQ1 of the power supply capacitor C11 becomes higher than the control voltage E1. Then, since the diode D11 is reverse-biased, the charging path (first path) of the power supply capacitor C11 by the control power supply circuit 14 is switched to the charging path (second path) of the power supply capacitor C11 by the auxiliary winding L3.

  When a predetermined period T1 has elapsed from the start of the operation of the apparatus, the control circuit 12 starts the start-up control of the discharge lamp 3 by switching on the switching elements Q11 and Q14 and switching off the switching elements Q12 and Q13. To do. As a result, the output voltage V2 of the inverter circuit 11 becomes the starting voltage V10 and is applied to the starting circuit 13. The predetermined period T1 is a time required for at least the charging voltage EQ1 of the power supply capacitor C11 to exceed the lower limit voltage at which the first drive circuit 110 can operate.

  At this time, the potential of the source terminal of the switching element Q11 rises to the starting voltage V10, but the auxiliary voltage V3 generated in the auxiliary winding L3 is applied to both ends of the power supply capacitor C11. Therefore, current can be supplied from the auxiliary winding L3 to the first drive circuit 110 regardless of the potential of the source terminal of the switching element Q11.

  Further, the current limiting resistor R1 is set to a resistance value such that the average current supplied from the auxiliary winding L3 to the power supply capacitor C11 at the time of starting becomes larger than the consumption current of the first drive circuit 110. Therefore, the operation of the first drive circuit 110 can be maintained by maintaining the charging voltage EQ1 of the power supply capacitor C11 in a state higher than the lower limit voltage at which the first drive circuit 110 can operate. Therefore, the output voltage V2 of the inverter circuit 11 can be maintained at the starting voltage V10. The auxiliary voltage V3 is limited to the Zener voltage VZ1 by the Zener diode ZD1. For this reason, the auxiliary voltage V3 does not exceed the withstand voltage of the first drive circuit 110.

  When the discharge lamp 3 is lit, the control circuit 12 controls on / off of the switching elements Q11 to Q14 so that an alternating voltage with a low frequency (for example, several hundred Hz to several kHz) is applied to the discharge lamp 3. . Then, the output voltage V1 of the DC power supply circuit 10 decreases from the starting voltage V10 to the lighting voltage V11. For example, if the discharge lamp 3 is a metal halide lamp that does not contain mercury, the lighting voltage V11 is 42V.

  At this time, the auxiliary voltage V3 generated in the auxiliary winding L3 is about 2.3 V, which is lower than the reference voltage VB1. Then, the switch SW1 of the first switching circuit 15 is switched off and the diode D11 is forward biased, so that the charging path (second path) of the power supply capacitor C11 by the auxiliary winding L3 is for power supply by the control power supply circuit 14. Switching to the charging path (first path) of the capacitor C11. That is, the first switching circuit 15 is configured to switch between a first path for charging the power supply capacitor C11 by the first drive power supply and a second path for charging the power supply capacitor C11 by the second drive power supply. It functions as “switching means”.

  As described above, in the discharge lamp lighting device 1 of the present embodiment, when the discharge lamp 3 is started, the power supply capacitor C11 is switched by the auxiliary voltage V3 generated in the auxiliary winding L3 that is switched to the second path and is the second drive power supply. Can be charged. For this reason, in the discharge lamp lighting device 1 of the present embodiment, it is not necessary to ensure the charging time of the power supply capacitor C11, and a DC starting method in which a DC voltage of one polarity is continuously applied to the discharge lamp 3 can be adopted. it can. Therefore, in the discharge lamp lighting device 1 of the present embodiment, it is possible to avoid the risk of the discharge lamp 3 going off due to the polarity reversal immediately after the start of discharge.

  Further, in the discharge lamp lighting device 1 of the present embodiment, the power supply capacitor C11 can be continuously charged by the auxiliary winding L3 that is the second drive power supply, so that it is not necessary to consider the discharge time in the first place. It is not necessary to prepare a large power supply capacitor C11. For this reason, in the discharge lamp lighting device 1 of this embodiment, the increase in cost accompanying the enlargement of the capacitor | condenser C11 for power supplies and the enlargement of an apparatus are not caused.

  That is, in the discharge lamp lighting device 1 of the present embodiment, it is possible to ensure the stability at the start of the discharge lamp 3 without increasing the capacitance of the power supply capacitor C11.

  Further, when the discharge lamp 3 is turned on, the power supply capacitor C11 is charged by the control power supply circuit 14 which is the first drive power supply. Therefore, when the discharge voltage 3 is turned on, the power supply capacitor C11 is connected via the current limiting resistor R1. C11 is not charged. For this reason, it is not necessary to set the current limiting resistor R1 in accordance with the lighting of the discharge lamp 3, so that the resistance value of the current limiting resistor R1 can be set large to reduce the circuit loss. If the resistance value of the current limiting resistor R1 is set so that a current slightly higher than the current consumption of the first drive circuit 110 (for example, 1.2 times or less) is supplied from the auxiliary winding L3, the circuit loss is reduced. be able to.

  Further, since the power supply capacitor C11 is charged by the control power supply circuit 14 even when the operation of the apparatus is started, even if the resistance value of the current limiting resistor R1 is increased, the rise of the charging voltage EQ1 of the power supply capacitor C11 is delayed. There is nothing.

  Here, when the discharge lamp 3 is started, the control circuit 12 maintains the output voltage V1 of the DC power supply circuit 10 at the starting voltage V10 by the boosting action by the switching operation of the switching element Q1. Therefore, the power supply capacitor C11 can be charged by the auxiliary voltage V3 generated in the auxiliary winding L3 while the switching element Q1 is turned off and the current is conducted to the secondary winding L2 of the transformer 100. For this reason, it is necessary to set the resistance value of the current limiting resistor R1 in consideration of the conduction period of the secondary winding L2.

  For example, the charging voltage EQ1 at the start of the discharge lamp 3 is 14 V, the average value of the conduction period of the secondary winding L2 with respect to the cycle of the intermittent operation of the switching element Q1 is 2%, and the current consumption of the first drive circuit 110 is Assume that the average value is 100 μA. In this case, the resistance value of the current limiting resistor R1 may be 3.6 kΩ or less. In this case, the instantaneous power consumption of the current limiting resistor R1 is as small as 93 mW and the average power consumption is as small as 1.9 mW, and the current limiting resistor R1 can be configured with a small size. Note that the loss in the Zener diode ZD1 in this case is 1.4 mW even if it is assumed that the consumption current of the first drive circuit 110 flows to the Zener diode ZD1 as it is, which is very small.

  Although not shown, the auxiliary voltage V3 generated in the auxiliary winding L3 may be rectified and smoothed and then applied to the power supply capacitor C11 via the current limiting resistor R1. In this configuration, the power supply capacitor C11 can be charged regardless of whether the switching element Q1 of the DC power supply circuit 10 is on or off. For this reason, the resistance value of the current limiting resistor R1 can be further increased, and the loss and stress in the current limiting resistor R1 can be further reduced.

(Embodiment 2)
Hereinafter, a discharge lamp lighting device 1 according to Embodiment 2 of the present invention will be described with reference to the drawings. However, since the basic configuration of the discharge lamp lighting device 1 according to the present embodiment is common to the discharge lamp lighting device 1 according to the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 3, in the discharge lamp lighting device 1 of the present embodiment, instead of providing the first switching circuit 15, both ends of the auxiliary winding L3 are connected to the power supply capacitor C11 via the diode D3 and the current limiting resistor R1. Connected in parallel.

  Hereinafter, operation | movement of the discharge lamp lighting device 1 of this embodiment is demonstrated using FIG. When the operation of the apparatus is started, the control circuit 12 switches on the low-side switching elements Q12 and Q14. As a result, the control voltage E1 is supplied to the power supply capacitors C11 and C13 via the diodes D11 and D13, and the charging voltages EQ1 and EQ3 of the power supply capacitors C11 and C13 rapidly rise to the control voltage E1.

  Thereafter, the control circuit 12 controls the switching element Q1 to start controlling the DC power supply circuit 10. Immediately after the start of the apparatus, the discharge lamp 3 is turned off. Therefore, the control circuit 12 raises the output voltage V1 of the DC power supply circuit 10 to the starting voltage V10. At this time, the auxiliary voltage V3 generated in the auxiliary winding L3 also increases.

  When the auxiliary voltage V3 becomes higher than the control voltage E1, the diode D3 is forward-biased, so that current starts to be supplied from the auxiliary winding L3 to the power supply capacitor C11 via the current limiting resistor R1. When the second current I2 supplied from the auxiliary winding L3 becomes larger than the consumption current I0 of the first drive circuit 110 and the charging voltage EQ1 of the power supply capacitor C11 becomes higher than the control voltage E1, the diode D11 is reversed. It becomes a bias. For this reason, the first current I1 supplied from the control power supply circuit 14 is substantially zero. That is, the charging path (first path) of the power supply capacitor C11 by the control power supply circuit 14 is substantially switched to the charging path (second path) of the power supply capacitor C11 by the auxiliary winding L3.

  When a predetermined period T1 has elapsed from the start of the operation of the apparatus, the control circuit 12 starts the start-up control of the discharge lamp 3 by switching on the switching elements Q11 and Q14 and switching off the switching elements Q12 and Q13. To do. As a result, the output voltage V2 of the inverter circuit 11 becomes the starting voltage V10 and is applied to the starting circuit 13.

  At this time, the potential of the source terminal of the switching element Q11 rises to the starting voltage V10, but the auxiliary voltage V3 generated in the auxiliary winding L3 is applied to both ends of the power supply capacitor C11. Therefore, current can be supplied from the auxiliary winding L3 to the first drive circuit 110 regardless of the potential of the source terminal of the switching element Q11.

  Further, the current limiting resistor R1 is set to a resistance value such that the second current I2 supplied from the auxiliary winding L3 to the power supply capacitor C11 at the time of starting becomes larger than the consumption current I0 of the first drive circuit 110. ing. Therefore, the operation of the first drive circuit 110 can be maintained by maintaining the charging voltage EQ1 of the power supply capacitor C11 in a state higher than the lower limit voltage at which the first drive circuit 110 can operate. Therefore, the output voltage V2 of the inverter circuit 11 can be maintained at the starting voltage V10. The auxiliary voltage V3 is limited to the Zener voltage VZ1 by the Zener diode ZD1. For this reason, the auxiliary voltage V3 does not exceed the withstand voltage of the first drive circuit 110.

  When the discharge lamp 3 is lit, the control circuit 12 controls on / off of each of the switching elements Q11 to Q14 so as to apply a low-frequency alternating voltage to the discharge lamp 3. Then, the output voltage V1 of the DC power supply circuit 10 decreases from the starting voltage V10 to the lighting voltage V11. At this time, the auxiliary voltage V3 generated in the auxiliary winding L3 also decreases and becomes lower than the control voltage E1. Then, since the diode D3 is reverse-biased and the diode D11 is forward-biased, the charging path (second path) of the power supply capacitor C11 by the auxiliary winding L3 is the charging path of the power supply capacitor C11 by the control power supply circuit 14 (second path). The first route is substantially switched.

  As described above, in the discharge lamp lighting device 1 of the present embodiment, the first path for outputting the first current I1 through the diode D11, and the second current I2 through the current limiting resistor R1 and the diode D3 are output. It is configured to switch to the second route. The discharge lamp lighting device 1 according to this embodiment switches the forward bias and the reverse bias of the diodes D3 and D11 based on the magnitude relationship between the control voltage E1 and the auxiliary voltage V3 when the discharge lamp 3 is started and when it is lit. Thus, each charging path is substantially switched. That is, in the discharge lamp lighting device 1 of the present embodiment, the diode D11 in the first path, the current limiting resistor R1, and the diode D3 in the second path function as “switching means”. For this reason, the discharge lamp lighting device 1 of the present embodiment can achieve the same effects as the discharge lamp lighting device 1 of the first embodiment.

(Embodiment 3)
Hereinafter, a discharge lamp lighting device 1 according to Embodiment 3 of the present invention will be described with reference to the drawings. However, since the basic configuration of the discharge lamp lighting device 1 according to the present embodiment is common to the discharge lamp lighting device 1 according to the first embodiment, common portions are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 5, the discharge lamp lighting device 1 of the present embodiment has a first output circuit 16 (second drive power supply) and a second switching circuit instead of providing the auxiliary winding L3 and the first switching circuit 15. 17 (switching means).

  The first output circuit 16 includes a series circuit of a capacitor C3 and a diode D4 connected in parallel with the diode D2 of the DC power supply circuit 10, and a series circuit of a diode D5 and a capacitor C4 connected in parallel with the diode D4. The The first output circuit 16 is a so-called charge pump type booster circuit that boosts the capacitors C3 and C4 by stepwise charging by the switching operation of the switching element Q1 of the DC power supply circuit 10.

  Hereinafter, the operation of the first output circuit 16 will be described. When the switching element Q1 of the DC power supply circuit 10 is on, the capacitor C3 is charged via the diode D4 by the charging voltage of the smoothing capacitor C1. When the switching element Q1 is switched off, the capacitor C4 is charged via the diode D5 by the charging voltage of the capacitor C3. Therefore, the first output circuit 16 outputs an auxiliary voltage V3 that is a difference between the output voltage V1 and a voltage higher than the output voltage V1 of the DC power supply circuit 10.

  The second switching circuit 17 includes a pnp transistor TR1. The auxiliary voltage V3 of the first output circuit 16 is input to the emitter terminal of the transistor TR1. Further, the output voltage V1 of the DC power supply circuit 10 is input to the base terminal via the Zener diode ZD2. The collector terminal is connected to a power supply capacitor C11 via a current limiting resistor R1 and a diode D3.

  Hereinafter, the operation of the discharge lamp lighting device 1 of the present embodiment will be described. When the operation of the apparatus is started, the control circuit 12 switches on the low-side switching elements Q12 and Q14. As a result, the control voltage E1 is supplied to the power supply capacitors C11 and C13 via the diodes D11 and D13, and the charging voltages EQ1 and EQ3 of the power supply capacitors C11 and C13 rapidly rise to the control voltage E1.

  Thereafter, the control circuit 12 controls the switching element Q1 to start controlling the DC power supply circuit 10. Immediately after the start of the apparatus, the discharge lamp 3 is turned off. Therefore, the control circuit 12 raises the output voltage V1 of the DC power supply circuit 10 to the starting voltage V10. At this time, the auxiliary voltage V3 output from the first output circuit 16 also increases.

  If the base-emitter voltage of the transistor TR1 is ignored, when the auxiliary voltage V3 exceeds the Zener voltage of the Zener diode ZD2, a base current flows through the transistor TR1 and the transistor TR1 is turned on. Then, current is supplied from the capacitor C4 to the power supply capacitor C11 via the current limiting resistor R1 and the diode D3, and the charging voltage EQ1 of the power supply capacitor C11 becomes higher than the control voltage E1. As a result, the diode D11 is reverse-biased, so that the charging path (first path) of the power supply capacitor C11 by the control power supply circuit 14 becomes the charging path (second path) of the power supply capacitor C11 by the first output circuit 16. Switch.

  When a predetermined period T1 has elapsed from the start of the operation of the apparatus, the control circuit 12 starts the start-up control of the discharge lamp 3 by switching on the switching elements Q11 and Q14 and switching off the switching elements Q12 and Q13. To do. As a result, the output voltage V2 of the inverter circuit 11 becomes the starting voltage V10 and is applied to the starting circuit 13.

  When the discharge lamp 3 is lit, the control circuit 12 controls on / off of each of the switching elements Q11 to Q14 so as to apply a low-frequency alternating voltage to the discharge lamp 3. Then, the output voltage V1 of the DC power supply circuit 10 decreases from the starting voltage V10 to the lighting voltage V11. At this time, the auxiliary voltage V3 output from the first output circuit 16 also decreases and becomes lower than the Zener voltage of the Zener diode ZD2. Then, the base current does not flow through the transistor TR1, and the transistor TR1 is turned off. As a result, the diode D11 is forward biased, and the charging path (second path) of the power supply capacitor C11 by the first output circuit 16 is switched to the charging path (first path) of the power supply capacitor C11 by the control power supply circuit 14.

  As described above, in the discharge lamp lighting device 1 of the present embodiment, the first output circuit 16 functions similarly to the auxiliary winding L3, and the second switching circuit 17 functions similarly to the first switching circuit 15. do. For this reason, the discharge lamp lighting device 1 of the present embodiment can achieve the same effects as the discharge lamp lighting device 1 of the first embodiment.

  In the configuration shown in FIG. 5, the transistor TR1 is turned on / off when the auxiliary voltage V3 exceeds the Zener voltage of the Zener diode ZD2, but other configurations may be used. For example, the anode of the zener diode ZD2 may be connected to GND (ground). In this configuration, when the sum of the output voltage V1 of the DC power supply circuit 10 and the auxiliary voltage V3 exceeds the Zener voltage of the Zener diode ZD2, the transistor TR1 is switched on / off. Alternatively, the anode of the Zener diode ZD2 may be connected to the power supply capacitor C11. In this configuration, when the difference between the auxiliary voltage V3 and the charging voltage EQ1 of the power supply capacitor C11 exceeds the Zener voltage of the Zener diode ZD2, the transistor TR1 is switched on / off.

  Here, as shown in FIG. 6, the discharge lamp lighting device 1 of the present embodiment has a second output circuit 18 in which a capacitor C5 and a diode D6 are further added to the first output circuit 16 instead of the first output circuit 16. A configuration using may be used. The second output circuit 18 is configured to have both a function of outputting the auxiliary voltage V3 and a function of outputting a power supply voltage for driving the starter circuit 13.

  Further, as shown in FIG. 6, the discharge lamp lighting device 1 of the present embodiment may have a configuration in which a Zener diode ZD3 is connected between a capacitor C4 and a diode D3 instead of the second switching circuit 17. . In this configuration, only when the auxiliary voltage V3 exceeds the Zener voltage of the Zener diode ZD3, current is supplied from the capacitor C4 to the power supply capacitor C11 via the current limiting resistor R1 and the diode D3. Instead of the Zener diode ZD3, a two-terminal bidirectional element that conducts when a specified voltage is exceeded, such as a diac, may be used.

  Further, as shown in FIG. 7, the discharge lamp lighting device 1 according to the present embodiment supplies a current to the power supply capacitor C11 through the diode D3 and the current limiting resistor R1 without providing the second switching circuit 17. It may be a configuration.

  The operation of this configuration will be described below with reference to FIG. When the discharge lamp 3 is started, the second current I2 supplied to the power supply capacitor C11 through the diode D3 and the current limiting resistor R1 is increased by the auxiliary voltage V3. Here, by setting the resistance value of the current limiting resistor R1 so that the second current I2 is larger than the consumption current I0 of the first drive circuit 110, the charging voltage EQ1 of the power supply capacitor C11 increases, and the control is performed. It becomes higher than the voltage E1. Then, since the diode D11 is reverse-biased, the first current I1 supplied from the control power circuit 14 is almost zero. That is, the charging path (first path) of the power supply capacitor C11 by the control power supply circuit 14 is substantially switched to the charging path (second path) of the power supply capacitor C11 by the first output circuit 16.

  The current limiting resistor R1 may be set to 4.5 MΩ or less when the average value of the current consumption I0 of the first drive circuit 110 is 100 μA. At this time, since the power consumption at the current limiting resistor R1 is as small as 45 mW, the current limiting resistor R1 can be configured with a small size. Further, the loss in the Zener diode ZD1 in this case is as small as 1.4 mW even if it is assumed that the consumption current I0 of the first drive circuit 110 flows to the Zener diode ZD1 as it is. Therefore, the Zener diode ZD1 can also be configured with a small size.

  When the discharge lamp 3 is lit, the output voltage V1 of the DC power supply circuit 10 decreases and the auxiliary voltage V3 also decreases. Since the auxiliary voltage V3 at the time of lighting is significantly lower than that at the time of start-up, the second current I2 is also greatly reduced and becomes smaller than the consumption current I0 of the first drive circuit 110. The current limiting resistor R1 is desirably set to a resistance value such that the second current I2 when the discharge lamp 3 is lit is at least smaller than half of the current consumption I0.

  Therefore, the current supplied to the power supply capacitor C11 is mainly the first current I1 supplied from the control power supply circuit 14. That is, the charging path (second path) of the power supply capacitor C11 by the first output circuit 16 is substantially switched to the charging path (first path) of the power supply capacitor C11 by the control power supply circuit 14. At this time, the charging voltage EQ1 of the power supply capacitor C11 becomes the control voltage E1.

  As described above, this configuration includes a charging path for the power supply capacitor C11 by the control power supply circuit 14 and a charging path for the power supply capacitor C11 by the first output circuit 16. In this configuration, the charging paths are substantially switched based on the magnitude of the auxiliary voltage V3 when the discharge lamp 3 is started and when it is turned on. For this reason, this structure can have the same effect as the discharge lamp lighting device 1 of the first embodiment.

  The capacitor C3 of the first output circuit 16 may be connected to an intermediate tap provided separately in the primary winding L1 of the transformer 100, instead of the connection point of the secondary winding L2 and the diode D1.

(Embodiment 4)
Hereinafter, a discharge lamp lighting device 1 according to Embodiment 4 of the present invention will be described with reference to the drawings. However, since the basic configuration of the discharge lamp lighting device 1 according to the present embodiment is common to the discharge lamp lighting device 1 according to the second embodiment, common portions are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 9, the discharge lamp lighting device 1 of the present embodiment is provided with a third output circuit 19 (second drive power supply) instead of providing the auxiliary winding L3. In the discharge lamp lighting device 1 of the present embodiment, the DC power supply circuit 10 is configured by a flyback converter.

  The third output circuit 19 is a charge pump type booster circuit, and includes a series circuit of a diode D7 and a capacitor C6. The third output circuit 19 is connected between the diode D1 of the DC power supply circuit 10 and the connection point of the switching element Q1 and the primary winding L1.

  The capacitor C6 of the third output circuit 19 is charged to substantially the same voltage as the output voltage V1 applied to both ends of the smoothing capacitor C1 of the DC power supply circuit 10 when the switching element Q1 is on. While the switching element Q1 is turned off and the secondary winding L2 is conducting, the voltage applied to the switching element Q1 is superimposed on the output voltage V1 at the connection point between the capacitor C6 and the current limiting resistor R1. A voltage is applied. Therefore, the auxiliary voltage V3 that is higher than the output voltage V1 by the voltage applied to the switching element Q1 is output from the third output circuit 19.

  In the discharge lamp lighting device 1 of the present embodiment, the charging path (first path) of the power supply capacitor C11 by the control power supply circuit 14 via the diode D11 and the power supply capacitor C11 by the third output circuit 19 via the diode D3. The charging path (second path) is provided. The discharge lamp lighting device 1 according to this embodiment switches the forward bias and the reverse bias of the diodes D3 and D11 based on the magnitude relationship between the control voltage E1 and the auxiliary voltage V3 when the discharge lamp 3 is started and when it is lit. Thus, each charging path is substantially switched. For this reason, the discharge lamp lighting device 1 of the present embodiment can achieve the same effects as the discharge lamp lighting device 1 of the second embodiment.

  Here, for example, the charging voltage EQ1 at the start of the discharge lamp 3 is 14 V, the average value of the ratio of the conduction period of the secondary winding L2 to the cycle of the intermittent operation of the switching element Q1 is 2%, and the first drive circuit 110 Assume that the average value of current consumption is 100 μA. In this case, the resistance value of the current limiting resistor R1 may be 13 kΩ or less. In this case, the average power consumption of the current limiting resistor R1 is as very small as 6.5 mW, and the current limiting resistor R1 can be configured in a small size.

  A rectification / smoothing circuit may be provided at the output terminal of the third output circuit 19. In this configuration, since the resistance value of the current limiting resistor R1 can be increased, the current limiting resistor R1 can be configured with a smaller size.

  Further, the capacitor C6 of the third output circuit 19 may be connected to an intermediate tap separately provided in the primary winding L1 of the transformer 100, instead of the connection point of the primary winding L1 and the switching element Q1. .

  In the discharge lamp lighting device 1 of the present embodiment, the output terminal of the DC power supply circuit 10 and the power supply capacitor C13 are connected via the current limiting resistor R2 and the diode D8. A zener diode ZD4 is connected in parallel to both ends of the power supply capacitor C13. As the Zener diode ZD4, the same one as the Zener diode ZD1 is selected. That is, in the discharge lamp lighting device 1 of the present embodiment, the output voltage V1 of the DC power supply circuit 10 is supplied to the other power supply capacitor C13 through the same circuit as the circuit including the current limiting resistor R1, the diode D3, and the Zener diode ZD1. Supply.

  This configuration is suitable, for example, when performing an operation of extending only the first cycle of the alternating voltage output from the inverter circuit 11 in order to quickly increase the temperature of the electrode of the discharge lamp 3 immediately after the discharge lamp 3 is turned on. . That is, in this case, since the period of the alternating voltage becomes longer, the discharge time of the power supply capacitor C13 also becomes longer, but the power supply capacitor C13 can be charged with a voltage higher than the control voltage E1 when the discharge lamp 3 is started. For this reason, it is possible to lengthen the time until the charging voltage EQ3 of the power supply capacitor C13 reaches the lower limit voltage at which the third drive circuit 130 can operate. Therefore, it is not necessary to prepare the power supply capacitor C13 having a large capacitance in consideration of the discharge time.

  The power supply capacitor C13 does not necessarily have to be charged with the output voltage V1 of the DC power supply circuit 10, and may have another configuration. For example, the anode of the diode D8 may be connected to the capacitor C6 of the third output circuit 19, and the power supply capacitor C13 may be charged by the auxiliary voltage V3. Moreover, the said structure which charges the capacitor | condenser C13 for power supplies is applicable not only to this embodiment but any discharge lamp lighting device 1 of Embodiment 1-3.

  The discharge lamp lighting device 1 of each of the above embodiments can be used for an illumination device such as a vehicle headlamp. Hereinafter, a vehicle headlamp 4 will be described with reference to the drawings as an example of a lighting device according to an embodiment of the present invention. As shown in FIG. 10A, the vehicle headlamp 4 according to this embodiment includes the discharge lamp lighting device 1 according to any of the above embodiments, the socket 30 in which the discharge lamp 3 is mounted, and the discharge lamp lighting. The apparatus 1 and the instrument main body 40 holding the socket 30 are provided. The discharge lamp lighting device 1 is connected to a battery 2 via a fuse F1 and a power switch S1. Therefore, the vehicle headlamp 4 is configured to be able to switch on / off the discharge lamp 3 by switching the power switch S1 on / off. The vehicle headlamp 4 is attached to the front portion of the vehicle 5 as shown in FIG.

  Note that the use of the discharge lamp lighting device 1 of each of the above embodiments is not limited to the vehicle headlamp 4 described above. For example, a vehicle interior lighting device such as a room lamp, a tail lamp, a vehicle width lamp, It can be widely used in an exterior light illumination device such as a brake lamp. Of course, you may use the discharge lamp lighting device 1 of each said embodiment for the illuminating device of general illumination uses other than the object for vehicles.

DESCRIPTION OF SYMBOLS 1 Discharge lamp lighting device 10 DC power supply circuit 11 Inverter circuit 12 Control circuit 13 Start-up circuit 14 Control power supply circuit (1st drive power supply)
15 1st switching circuit (switching means)
2 Battery (DC power supply)
3 Discharge lamp Q11, Q13 High-side switching element C11, C13 Power supply capacitor L3 Auxiliary winding (second drive power supply)

Claims (5)

A DC power supply circuit that outputs a DC voltage; an inverter circuit that converts the output voltage of the DC power supply circuit into an alternating voltage and outputs the alternating voltage; and a high voltage pulse generated by receiving the output voltage of the inverter circuit, A starting circuit for starting a discharge lamp, and a control circuit for controlling each output of the DC power supply circuit and the inverter circuit,
The inverter circuit continuously outputs a DC voltage of one polarity at the start of the discharge lamp,
The inverter circuit includes a bridge circuit composed of at least two or more switching elements, a plurality of driving circuits that respectively drive the switching elements, and the driving circuit that drives the high-side switching element among the switching elements. And a power supply capacitor for supplying an operating voltage to
A first drive power source that outputs a predetermined voltage; and a second drive that outputs a voltage proportional to the output voltage of the DC power supply circuit and higher than the voltage output by the first drive power source at least when the discharge lamp is started. Switching means for switching between a power supply, a first path for charging the power supply capacitor with the first drive power supply, and a second path for charging the power supply capacitor with the second drive power supply;
The discharge lamp lighting device, wherein the switching means switches to the second path when the discharge lamp is started.   2. The discharge lamp according to claim 1, wherein the second driving power source includes an auxiliary winding separately provided in a transformer or an inductor included in the DC power source circuit and electrically insulated from the DC power source circuit. Lighting device.   2. The discharge lamp lighting device according to claim 1, wherein the second drive power source includes a charge pump type booster circuit that is connected to the DC power source circuit and boosts and outputs an output voltage of the DC power source circuit. . The second path is a path for supplying a current from the second drive power supply to the power supply capacitor via a current limiting resistor,
The switching means switches to the second path when the voltage output from the second drive power supply becomes higher than the voltage output from the first drive power supply, and the voltage output from the first drive power supply changes to the second drive power supply. 4. The discharge lamp lighting device according to claim 1, wherein the discharge lamp lighting device is configured to switch to the first path when the voltage becomes higher than a voltage output from the first path. 5.   The discharge lamp lighting device according to any one of claims 1 to 4, a socket to which the discharge lamp is mounted, and an appliance main body that holds the discharge lamp lighting device and the socket. Lighting device.

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